Electrical impedance tomography (EIT) is a method in which a weak alternating electric current is introduced into the human body in order to measure the surface potentials at different points of the body. By rotating the sites at which the current is introduced around the body while measuring the surface potentials at the same time, a two-dimensional tomogram of the electrical impedance distribution in the body being examined can be determined by means of suitable mathematical reconstruction algorithms. A tomogram of the impedance distribution of the human body is of interest in medicine because the electrical impedance changes with both the content of air and the extracellular fluid content in the tissue. The ventilation of the lungs and the shifts in the blood and serum can thus be imaged and monitored in a regionally resolved manner.
To make it possible to carry out the measurement, the electrodes must be able to be arranged on the test subject's body in a simple manner. It is known that the electrodes may be arranged on a belt that can be placed around the test subject's body.
Such a belt, hereinafter called an electrode belt, has become known from EP 1 000 580 A1. An electrode holder with typically 16 electrodes is arranged on a test subject such that it fully encloses the circumference of the body. The electrode belt is connected via a feed line to an evaluating unit, in which the tomogram for the body section being examined is calculated.